Nuke-frying raygun 747 all ready bar the raygun

World's most expensive laser pointer, until '09

The Pentagon's astounding flying raygun programme has passed its penultimate technical milestone, according to makers Boeing.

The Airborne Laser (ABL) project is intended to deliver a fleet of aircraft armed with high-powered energy weapons. The idea is that such aircraft would patrol up to 400km from the launch sites of enemy nuclear missiles - off the coast of North Korea, say. Should the rogue state in question launch an atomic barrage, the ABLs would detect the hot exhaust plumes on infrared and focus their high-intensity energy beams on the vulnerable ballistic missiles while they were still packed with explosive rocket fuel - so blasting them to smithereens almost instantly, long before they could reach orbit and separate into pesky multiple warheads.

The laser jumbo - now with everything but the laser.

There are a few little technical snags to be overcome here, however. At present, the only type of laser that offers a serious chance of cooking off even fairly explosive targets at 400km is the Chemical Oxygen Iodine Laser (COIL). COIL blasters are big and heavy, and need lots of quite dangerous hazmat fuel to operate; they also produce large amounts of toxic exhaust. For this reason, the carrying aircraft for the ABL needs to be a converted jumbo jet, as few other aeroplanes could lift the ray-cannon and its fuel.

Then there are difficulties with detecting the target and successfully pointing the laser at it. These at least, according to a Boeing release, have now been surmounted. The prototype blaster jumbo, which has its detection and aiming systems fitted but not the kill-ray itself, has been flying for some time. Now Boeing says that it has successfully carried out successful "low-power system flight tests."

Operating from Edwards airforce base in California, the 747 apparently used its infrared detectors to locate an "instrumented target board" mounted on a test aeroplane. It then lit the target up using its aiming and tracking lasers, which are used to lock onto the target and measure atmospheric effects so as to direct the COIL beam correctly. Not yet having its chemical-fuelled main armament fitted, the ABL instead used an ordinary solid-state laser in its place, to prove the system could light up the target - presumably much to the relief of those aboard the test aircraft.

"The completion of low-power system flight tests is a key milestone for the Airborne Laser team," said Pat Shanahan, Boeing veep for missile-busting.

"These tests demonstrate that ABL can fully engage a threat missile with its battle management and beam control/fire control systems. We are now ready to install the high-energy laser in the aircraft."

According to Boeing, the Northrop-Grumman made COIL cannon has already had successful ground tests. Boeing and the Pentagon expect to have it fitted in the ABL ready for a proper test against an actual ballistic missile in 2009. But then, they said 2005 a while back.

Even if the ABL works on time and to spec, it may have a rough ride ahead. Critics have suggested that a biggish fleet of raygun jumbos would be necessary to provide constant presence near countries of concern, and have pointed out that many adversaries (Russia, China, etc) could easily site their launch silos deep within their own airspace, meaning that US aerial blaster patrols would need to enter hostile airspace to be useful - perhaps precipitating the very attack they sought to prevent.

In response, the Pentagon says it isn't bothered about big, relatively chilled countries such as Russia and China. It argues that its entire missile-defence programme - of which the ABL is only one part - is intended purely to deal with the nuclear threat from smaller, more erratic nations such as Iran or North Korea.

This certainly rings true in the case of Russia, with thousands of warheads at its disposal. The ABL and its space-intercept and terminal-defence backstops - as currently envisaged, anyway - wouldn't have a prayer of standing off the Kremlin's Strategic Rocket Forces. Nor could they deal with submarine-launched missiles, unless some way was found to locate the subs.

China, with only a limited number of land-based weapons and no credible subs, might reasonably feel worried that the US missile defences will rob it of some options. On the other hand, if the country did get in a serious scuffle with America, the Chinese could always cut off the supply of iPods, bras etc, thus crippling the US consumer economy.

Boeing, for the company's part, suggests that "ABL's speed, precision and lethality also have potential for other missions, including destroying air-to-air, cruise and surface-to-air missiles."

Well, air-to-air and surface-to-air anyway: those have easy-to-spot hot exhaust plumes. Boeing seem to be implying that the blaster jumbo might be able to take on enemy air-superiority forces alone, rather than needing a fighter escort. That said, in its primary mission the ABL would need to conserve its chemical laser fuel.

If the amazing flying raygun really does work, it could upset calculations in ordinary air warfare, as well as nuclear-apocalypse brinkmanship. But it has to be said, conventional air warfare is hardly the most important challenge facing the USA at the moment. And it remains to be seen whether the ABL will work.®